M11S2: Urinary System: Kidneys

Question 1

The kidney

Answer 1

-organs that mark the beginning of the urinary system
-function: filter the blood to produce urine
Urine excreted from body through a series of tubes and organs
-in this way, body can get rid of water and excess ions
*refer to goodnotes

Question 2

Kidney: location and size

Answer 2

-pair of bean-shaped organs in abdominal region that located on either side of spine at level T12-L2 vertebrae
-roughly “fist-sized” organs that lay against posterior abdominal wall
Average size:
12 cm in length
6.5 cm in width
2.5 cm in thickness
*refer to goodnotes

Question 3

Kidney: surface anatomy

Answer 3

-medially, kidney have a concave surface where renal arteries and nerves enter and renal veins as well as the ureters exit
-medial surface = hilum of kidney
-hilum continuous with internal space in each kidney called renal sinus which filled with fatty tissue
*refer to goodnotes

Question 4

Kidney: supportive tissues

Answer 4

-each kidney surrounded by supportive tissue layers that protect and cushion kidneys

Renal capsule
-aka fibrous capsule
-covers outer surface of kidney
-composed of dense, irregular connective tissue
-this type of connective tissue functions to protect the kidneys from injury and pathogens, as well as to maintain shape of kidneys

Adipose capsule
Aka perinephric fat
-layer of adipose tissue external to renal capsule
-offers cushion and protection by completely surrounding kidney

*refer to goodnotes

Question 5

Internal anatomy of kidney

Answer 5

-divided into separate regions called cortex and medulla
-cortex = makes up outer layer of kidney
-medulla = deep to cortex
These regions filter blood to make urine
*refer to goodnotes

Question 6

Internal anatomy of kidney: lobes

Answer 6

-extensions of cortex called renal columns seperate medulla into renal pyramids
-apex (tip of phyramidal) termed the renal papilla
-so kidney divided into renal lobes
-each lobe consists of renal phyramid, its overlying cortex and surrounding renal column
RENAL LOBE
*refer to goodnotes

Question 7

Renal pelvis

Answer 7

-urine produced in kidneys flows through renal papilla into funnel shaped space termed the minor calyx
-each minor calyx drains into major calyx and then into large renal pelvis, which continues on as the ureter
*refer to goodnotes

Question 8

Kidney blood supply and drainage

Answer 8

-after kidney filters blood, flow to and from these organs very important

Blood supply
-kidneys receives their blood supply from paired renal arteries which are branches of abdominal aorta

Blood drainage
-kidneys drained by renal veins, which are anterior to arteries and drain into inferior vena cava (IVC)

(Due to the function of kidneys to filter blood, they receive 20-25% of cardiac output, which about 1-1.2 L of blood per minute)
*refer to goodnotes

Question 9

Kidney histology: the nephron

Answer 9

-kidney made up of millions functional units known as nephrons
-these units filter blood and produce urine
-nephron composed of 2 parts:

Renal corpuscle
-composed of 2 structures: glomerulus and glomerular capsule (bowman’s capsule)
-glomerulus consists of bundle of capillaries enclosed with glomerular capsule
-capsule creates a space between its walls and the glomerular capillaries called capsular (bowman’s) space
-blood flows in kidney and to the glomerular capillaries
-filtration occurs when components of blood move out from capillary into the bowman’s space
-material in Bowman’s space known as filtrate
-capillaries of glomerulus have small holes (fenestrations) that allow ions, water, and other molecules to move through their membranes
-glomerular capillaries also surrounded and supported by specialized cells called podocytes
-these cells wrap their foot-like processes around the glomerular capillaries creating filtration sits that permit the passage of water and salts and restrict the passage of proteins

Renal tubule
-extends throughout cortex and medulla of kidney
-divided into 3 sections: the proximal convoluted tubule, the loop of henle, and distal convoluted tubule
-each section has specific function in reabsorption or secretion of substances like ions, proteins and water to and from filtrate
*refer to goodnotes

Question 10

The collecting system

Answer 10

-from renal tubules, filtrate travels into collecting tubule and then to the collecting ducts that travel within the renal medulla
-final processing of filtrate occurs in collecting duct where it further modified
-once filtrate leaves the collecting duct at the renal papilla it can be called urine
*refer to goodnotes

Question 11

The juxtaglomerular apparatus monitors blood pressure

Answer 11

-specialized structural unit that regulates the blood pressure of body by monitoring ion concentration in filtrate

Juxtaglomerular cells
-modified smooth cells of afferent arteriole (a smaller artery that brings blood into the glomerulus)

Manila densa
-modified cuboidal cells of distal convoluted tubule
*refer to goodnotes

Question 12

Review the kidney

Answer 12

-organs that filter blood to rid the body of waste, balance ion concentration and body fluid volume and produce erythropoietin (a hormone that stimulates the production ofred blood cells)
-they produce iron via nephrons, and pass the filtrate on to the minor and major calyces, and into the renal pelvis where it drains into ureters
*refer to goodnotes